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1.
TheN2Omoleculeplaysaveryimportantroleinozonechemistryintheatomosphere.Itsrovibrationalspectracanprovideusefulinformationabouttheintramoleculardynamicproperties.N2Oisalinearmoleculeattheequilibriumgeometryfortheelectronicgroundstate.Numerousinvestigatio…  相似文献   

2.
1INTRODUCTIONTheNi(dmit)2moleculesgiverisetoanumberofmolecularconductors〔1,2〕inadditiontosuperconductors〔3,4〕.Themultysulfurf...  相似文献   

3.
IntroductionOrganometallicandcoordinationcomplexeshavere centlyemergedaspotentialbuildingblocksfornonlinearoptical (NLO )materials .1 6Comparedwithorganicmolecules ,metalcomplexescanhavealargervarietyofstructuresandamuchgreaterdiversityoftunableelec tronic…  相似文献   

4.
IntroductionInthepastseveralyears ,considerableprogresshasbeenachievedincontrollingtheassemblyofindividualbuildingblocksintostructureswithspecifictopologiesandinterestingpropertiessuchasmolecularrecognition ,ionexchangeandselectiveguestinclusion .1 3 Itis…  相似文献   

5.
Organiclight emittingdiodes (OLEDs)usingsmallorganicmoleculeshavereceivedconsiderableinterestaftertheinitialworkbyTangetal.1in 1987,forthepotentialofusingthesedevicesaslow costalternativeinlighting ,backlightandflatpaneldisplays .Muchprogresshasbeenmaderecen…  相似文献   

6.
IntroductionThealkalihalidediatomicmoleculesprovideatypicalcurvecrosingproblem[1].Theoutstandingnonadiabaticbehaviorofthechem...  相似文献   

7.
Hydrodesulfurization of Thiophene on Ni,Mo-supported MCM-41 Catalysts   总被引:1,自引:0,他引:1  
IntroductionTherecentdiscoveryofnovelextralargemesoporousMCM-41molecularsieves[1,2]filsthegapbetweenmicroporousandmacroporous...  相似文献   

8.
IntroductionThemethodofseparatingaracemicmixtureintoitsenantiomersthroughtheformationofdiastereomericmolecularcomplexbyreactionwithanopticallyactivecompoundhasbeenwidelyinvestigated .Fromthepointofviewofcrystallography ,anessentialprerequisiteofthesucc…  相似文献   

9.
李前忠  罗辽复  张利绒 《中国化学》2002,20(12):1506-1513
IntroductionThekineticfeatureofligandinteractionswithmacro moleculeplaysasignificantroleinbiologicalregula tion .1,2 Multisubunitproteinssuchashumanhemoglobinfrequentlyexhibitcooperativity ,3 6whicharisesfromacouplingbetweentheeffectsofligandbindingatthein…  相似文献   

10.
郭礼伟  高翔  张丹维  吴世晖  吴厚铭 《中国化学》2002,20(11):1430-1433
IntroductionPodophyllotoxin (1)isawellknownnaturalproductendowedwithpotentantineoplasticactivity .1Thesynthe sisandpreparationofdifferenttypesofderivativesofthismoleculehavebeenattractingmuchinterestofbothorgan icchemistsandmedicinalchemists .2 Inthispaper …  相似文献   

11.
A novel complex [Cu(NnpPy)2(HlTCB)(H1O)]·2H2O (NITpPy = 2‐(pyrid‐4′‐yl)‐4,4,5,5‐tetramethyl‐1, 3‐dioxoimidazoline; H2TCB = 1, 5‐dicarboxybenzene carboxylic‐2, 4‐diacid) has been synthesized and characterized by X‐ray crystallography analysis. The crystal structure consists of infinite chains of Cu‐(NITpPy)2(H2O) units linked by H2TCB ligands. The complex crystallizes in triclinic system with space group PI. Crystal data: a = 1.0594(2) nm, b = 1.3830(3) nm, c = 1.5551(3) nm, a = 67.75(3)°, β = 89.83(3)°, γ = 70.54(3)°. The variable magnetic susceptibility studies lead to magnetic coupling constant values of J1= ?11.18 cm‐1 (Cu—Rad) and J2 = ?4.06 cm?1 (Cu—Cu).  相似文献   

12.
The Crystal Structures of [Cu2Cl2(AA · H+)2](NO3)2 and [AA · H+]Picr? (AA · H+ = Allylammonium; Picr? = Picrat) By an alternating current electro synthesis the crystal-line π-complex [Cu2Cl2(AA · H+)2](NO3)2 has been obtained from CuCl2 · 2H2O, allylamine (AA), and HNO3 in ethanolic solution. X-ray structure analysis revealed that the compound crystallized in the monoclinic system, space group P21/a, a = 7.229(3), b = 7.824(3), c = 26.098(6) Å, γ = 94.46(5)°, Z = 4, R = 0.025 for 2 023 reflections. The crystal structure is built up of CunCln chains which are connected by π-bonding bidentate AA · H+ …? ON(O)O …? H+ · AA units. For comparision with the above complex the structure of [AA · H+]Picr? (Picr? = picrate anion) is also reported.  相似文献   

13.
Light‐yellow single crystals of the mixed‐valent mercury‐rich basic nitrate Hg8O4(OH)(NO3)5 were obtained as a by‐product at 85 °C from a melt consisting of stoichiometric amounts of (HgI2)(NO3)2·2H2O and HgII(OH)(NO3). The title compound, represented by the more detailed formula HgI2(NO3)2·HgII(OH)(NO3)·HgII(NO3)2·4HgIIO, exhibits a new structure type (monoclinic, C2/c, Z = 4, a = 6.7708(7), b = 11.6692(11), c = 24.492(2) Å, β = 96.851(2)°, 2920 structure factors, 178 parameters, R1[F2 > 2σ(F2)] = 0.0316) and is made up of almost linear [O‐HgII‐O] and [O‐HgI‐HgI‐O] building blocks with typical HgII‐O distances around 2.06Å and a HgI‐O distance of 2.13Å. The Hg22+ dumbbell exhibits a characteristic Hg‐Hg distance of 2.5079(7) Å. The different types of mercury‐oxygen units form a complex three‐dimensional network exhibiting large cavities which are occupied by the nitrate groups. The NO3? anions show only weak interactions between the nitrate oxygen atoms and the mercury atoms which are at distances > 2.6Å from one another. One of the three crystallographically independent nitrate groups is disordered.  相似文献   

14.
A three‐dimensional cyano‐bridged copper(II) complex, [Cu(dien)Ag(CN)2]2[Ag2(CN)3][Ag(CN)2] ( 1 ) (dien = diethylenetriamine), has been prepared and characterized by X‐ray crystallography. Complex 1 crystallized in the monoclinic space group P21/n with a = 6.988(2), b = 17.615(6), c = 12.564(4) Å, β = 90.790(5)°. The crystal consists of cis‐[Cu(dien)]2+ units bridged by [Ag(CN)2] to form a zig‐zag chain. The Ag atoms of the free and bridging [Ag(CN)2] link together to form additional infinite zig‐zag chains with short Ag···Ag distances. The presence of Ag···Ag interactions effectively increases the dimensionality from a 1‐D chain to a 3‐D coordination polymer.  相似文献   

15.
In the course of investigations relating to magnesia oxysulfate cement the basic magnesium salt hydrate 3Mg(OH)2 · MgSO4 · 8H2O (3–1–8 phase) was found as a metastable phase in the system Mg(OH)2‐MgSO4‐H2O at room temperature (the 5–1–2 phase is the stable phase) and was characterized by thermal analysis, Raman spectroscopy, and X‐ray powder diffraction. The complex crystal structure of the 3–1–8 phase was determined from high resolution laboratory X‐ray powder diffraction data [space group C2/c, Z = 4, a = 7.8956(1) Å, b = 9.8302(2) Å, c = 20.1769(2) Å, β = 96.2147(16)°, and V = 1556.84(4) Å3]. In the crystal structure of the 3–1–8 phase, parallel double chains of edge‐linked distorted Mg(OH2)2(OH)4 octahedra run along [–110] and [110] direction forming a pattern of crossed rods. Isolated SO4 tetrahedra and interstitial water molecules separate the stacks of parallel double chains.  相似文献   

16.
The title complex {[Co(dimb)2(H2O)2]·(NO3)2·(H2O)2}n ( 1 ) (dimb = 1,3‐di(imidazol‐1‐ylmethyl)‐5‐methylbenzene) has been hydrothermally synthesized by the reaction of dimb with Co(NO3)2·6H2O in aqueous solution. The cobalt(II) atoms are linked by bridging dimb ligands to form 2D corrugated and wavy networks containing Co4(dimb)4 macrocyclic motifs. Two neighboring independent layers interlinked each other in a parallel fashion to construct three‐dimensional structure by O–H···O, N–H···O and C–H···O hydrogen bonds. Magnetic measurement shows the weak antiferromagnetic interaction with a one‐dimensional chain model in the range of 5–300 K, with J of –0.68 cm−1.  相似文献   

17.
3‐Nitro‐1,2,4‐triazol‐5‐one (NTO) europium complex of [Eu(NTO)3(H2O)5]·5H2O was synthesized by mixing the aqueous solution of lithium 3‐nitro‐1,2,4‐triazol‐5‐onate and the dilute nitric acid solution of europium oxide. The title complex was characterized by elemental analysis and IR spectra. The single crystal structure was determined by a four‐circle x‐ray diffractometer. The title complex is monoclinic with space group P21/n and unit cell parameters of a = 1.8720(2) nm, b = 0.6548(3) nm, c = 1.9323(3) nm and β = 95.33(1)°. The coordination geometry around the europium ion is a distorted dodecahedron and there are five crystalline water molecules to form the stable structure of the crystal. From measurements of the enthalpy of solution in water at 298.15 K, the standard enthalpy of formation, lattice enthalpy and lattice energy have been determined as ‐(3798.6 ± 3.7), ?4488.4 and ?4452.4 kJ·mol?;1, respectively.  相似文献   

18.
Concentrated aqueous solutions of magnesium chloride and calcium nitrate, respectively, allow on addition of the potassium salt of tetrathiosquarate, K2C4S4 · H2O, the isolation of the earth alkaline salts MgC4S4 · 6 H2O ( 1 ) and CaC4S4 · 4 H2O ( 2 ) as orange and red crystals. The crystal structure determinations ( 1 : monoclinic, C2/c, a = 17.2280(7), b = 5.9185(2), c = 13.1480(4) Å, β = 104.730(3)°, Z = 4; 2 : monoclinic, P21/m, a = 7.8515(3), b = 12.7705(5), c = 10.6010(4) Å, β = 93.228(2)°, Z = 4) show the presence of C4S42? ions with almost undistorted D4h symmetry having average C–C and C–S bond lengths of 1.451Å and 1.659Å for 1 and 1.451Å and 1.655Å for 2 . The structure of 1 contains discrete, octahedral [Mg(H2O)6]2+ complexes. Several O–H····O and O–H····S bridges with H····O and H····S distances of less than 2.50Å connect cations and anions. The structure of 2 is built of concatenated, edge‐sharing Ca(H2O)6S2 polyhedra. The Ca2+ ions have the coordination number eight, C4S42? act as a chelating ligands towards Ca2+ with Ca–S distances of 3.14Å. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.  相似文献   

19.
A novel La( III )‐Cu( II ) heterometallic coordination polymer {[LaCu2(NTA)2(4,4′‐bpy)(H2O)3]NO3·5H2O]n, where H3NTA denotes nitrilotriacetic acid and 4,4′‐bpy denotes 4, 4‐bipyridine, was synthesized and characterized by IR spectrum, elemental analysis and X‐ray diffraction. The complex crystallizes in the triclinic space group Pi with cell parameters a = 1.33710(10) nm, b = 1,44530(10) nm, c =1.0949(2) nm, α = 71.905(7)°, β = 74.327(7)°, γ = 64.427(9)°, V = 1.7912(4) nm3and Z = 2. It consists of heterometallic units, in which each La( II ) ion is coordinated in a distorted monocapped square antiprism by three oxygen atoms from water molecules and six carboxyl oxygen atoms from five NTA3? ions, and each Cu( I ) ion is coordinated by one nitrogen atom from 4,4′‐bpy and one nitrogen atom, three oxygen atoms from NTA3?. In the title complex, La( I ) ions and Cu( II ) ions are connected by the heterometallic bridging of NTA3?, constructing a two‐dimensional network structure along the [110]. And it is extended into an infinite three‐dimensional network structure by the formation of homometallic bridging of Cu‐4, 4′‐bpy‐Cu, exhibiting a certain inclusion ability.  相似文献   

20.
A new cyano‐bridged binuclear 4f‐3d complex Sm(DMSO)4‐(H2O)3Cr(CN)6 was synthesized and characterized by single crystal structure analysis. It crystallizes in monoclinic, space group P21 with a=0.9367(2) nm, b = 1.3917(3) nm, c = 1.1212(2) run, β = 99.88(3)° and Z = 2. In this binuclear complex, Sm atom is eight coordinated and linked to the Cr atom by a cyano bridge. The molecules packs to form 3D structure due to the hydrogen bonds among them. [K3(18‐C‐6)3(H2O)4]Cr(CN)6·3H2O (18‐C‐6 represents 18‐crown‐6‐ether) that was synthesized as a byproduct in the preparation of a Gd—Cr complex is also structurally characterized. Crystal data: triclinic, space group P‐l with a = 1.0496(7) nm, b= 1.1567(14) nm, c = 1.3530(13) nm, a = 94.15(9)°, β = 96.04(8)°, γ = 95.25(9)° and Z = l. [K3(18‐C‐6)3(H2O)4]‐Cr(CN)6·3H2O consists of ionic [K3(18‐C‐6)3(H2O)4]3+ and [Cr(CN)6]3‐ pairs, of which the [K3(18‐C‐6)3(H2O)4]3+ ion is a trinuclear duster connected by water, and K atoms are eight coordinated by eight oxygen atoms of one 18‐C‐6 and two water molecules.  相似文献   

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